What is the difference between work function and threshold frequency?

The threshold frequency is the minimum frequency of radiation required to raise the potential energy of the most energetic electrons in a metal to zero, therefore giving the free electron (once emitted) a velocity of zero. The work function of a metal surface is the energy required to remove the most energetic electron from it. Each metal has a different work function, with the negative of this the maximum potential of the de-localised electrons in the metal. W=hf0 The formula: Kmax = hf - W (in Joules) gives the maximum kinetic energy of the electron. As h is Planck's constant, and f is the frequency provided to the metal (ie. frequency of the electromagnetic wave that had irradiated the metal), and W is the Work Function of the metal, if the frequency provided to the metal is the threshold frequency, then the electron has kinetic energy of zero. However, if more than the threshold frequency is provided, the electron will have a kinetic energy > 0. I hope that's explained okay! Bec